Display Device RTC Usage Management via Preliminary Action
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Solution Overview
Problem
Existing display devices, such as projectors, face challenges in confirming whether they are being used within their valid time limit due to unreliable built-in real-time clocks, especially when internet access is limited or when synchronization with external secure clocks is time-consuming, leading to user inconvenience and potential illicit use.
Innovation Solution
A display device equipped with a real-time clock and a control unit that displays an image corresponding to an input video signal when the clock status is invalid, utilizing a secure clock from an external source to manage usage validity and synchronize the built-in clock, ensuring quick and secure operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the projector uses a built-in RTC without battery backup to reduce cost, then the projector price is reduced and maintenance is simplified, but the RTC cannot retain time values after power depletion, making it impossible to confirm usage within time limits
Solution Approach 1:
The patent applies preliminary action by having the control unit check the RTC validity flag before attempting to use the RTC for usage confirmation. When the flag indicates invalid status (power depletion detected), the system proactively switches to alternative time sources or displays notifications, preventing failure rather than reacting to it. This resolves the contradiction by preparing advance应对措施 for the RTC's inability to retain time values.
Solution Approach 2:
The patent introduces an intermediary mechanism - the RTC validity flag and control unit logic - that mediates between the built-in RTC and the usage confirmation function. When the RTC becomes invalid after power depletion, the flag signals the control unit to use alternative approaches (external secure clock, notification display), thus maintaining usage confirmation reliability without requiring expensive battery-backed RTC hardware.
2Duration of action of stationary object
If the projector uses a super capacitor to back up the built-in RTC, then the RTC can retain time values for about two weeks, but the projector must be activated frequently to maintain power, and usage confirmation becomes difficult after two weeks of inactivity
Solution Approach 1:
The system performs preliminary action by checking the RTC validity flag and activation history before relying on RTC time for usage confirmation. When the super capacitor is depleted (indicated by invalid flag), the system proactively switches to alternative time sources rather than attempting to use unreliable RTC data, eliminating the need for frequent activation to maintain RTC accuracy.
Solution Approach 2:
The patent treats the super capacitor-backed RTC as a short-living component that is intentionally allowed to deplete after extended inactivity. Rather than maintaining it through frequent activation, the system accepts its limited lifespan and switches to alternative time sources when it fails, providing a cost-effective solution that avoids the complexity of frequent user intervention.
3Reliability
If the projector synchronizes with an external secure clock via NTP server, then accurate time for usage confirmation is obtained, but boot-up time increases and stress is placed on the user
Solution Approach 1:
The patent applies preliminary action by checking the RTC validity flag and external secure clock availability during system initialization but before full operation. When the RTC is valid and external synchronization is unavailable, the system proactively uses the built-in RTC immediately, avoiding unnecessary network access and reducing boot-up time. This resolves the contradiction by preparing advance decisions about time source selection.
Solution Approach 2:
The system performs partial synchronization - only attempting external NTP synchronization when absolutely necessary (when RTC is invalid or usage confirmation is critically needed). In normal operation with valid RTC, the system uses the built-in clock without excessive external communication, thus maintaining accuracy when needed while minimizing boot-up time and network stress in routine operations.
4Reliability
If the projector manages setting changes of the built-in RTC including monthly accuracy rate and security logs, then usage confirmation reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the complex RTC management functions (monthly accuracy rate management, security log recording, authority management) from the basic projector system. These functions are implemented only when absolutely necessary - specifically when the RTC validity flag indicates problems or when usage confirmation is critically required. This selective extraction maintains reliability when needed while avoiding the constant overhead of complex management systems, thus controlling manufacturing costs.
Solution Approach 2:
The system treats detailed RTC setting management and security logging as optional, short-living functions that are activated only when the built-in RTC encounters problems or when external synchronization fails. In normal operation with valid RTC, these expensive management functions remain dormant, providing reliability enhancement only when necessary rather than continuously, thus balancing cost and reliability.
Data Source
AI summary
Provided is a display device that has a usage validity period and confirms that the device is within the usage validity period when it is used, and can be improved in usefulness and can be used quickly, as well as a usage management method and program for the display device. The display device includes: a real-time clock; and, a control unit that, upon receiving a video display-ON signal for turning on video display under the condition that the status of the real-time clock is invalid, displays video corresponding to an input video signal.